Swash plate type compressor in which lubricating oil is effectively supplied to a shoe mechanism interposed between a piston and a swash plate

Abstract

In a swash plate type compressor in which a shoe mechanism ( 23 a and 23 b ) is slidably interposed between a swash plate ( 21 ) and a piston ( 22 ) to convert a rotating motion of the swash plate to a reciprocating motion of the piston, lubricating oil is effectively supplied together with a blowby gas to the shoe mechanism. As a result, the lubricating oil favorably lubricates a sliding portion which is between the shoe mechanism and each of the swash plate and the piston. The piston is inserted in a cylinder bore ( 1 ) of a cylinder block ( 2 ) to have a sealed gap around the piston. When the swash plate is rotatably driven, the piston is reciprocated through the shoe mechanism to compress a gaseous fluid including the lubricating oil. A part of the gaseous fluid passes as the blowby gas through the sealed gap during the reciprocation motion of the piston.

What is claimed is:  
     
       1. A swash plate type compressor for compressing a gaseous fluid including lubricating oil, said swash plate comprising: 
       a cylinder block defining a cylinder bore;  
       a piston inserted in said cylinder bore to have a scaled gap around said piston and reciprocating to compress said gaseous fluid, said gaseous fluid having a part which passes as a blowby gas through said sealed gap when said piston is reciprocated;  
       a swash plate rotatably driven;  
       a shoe mechanism slidably interposed between said swash plate and said piston for converting a rotating motion of said swash plate to a reciprocating motion of said piston; and  
       supply means connected to said sealed gap for supplying said blowby gas together with said lubricating oil to said shoe mechanism to lubricate a sliding portion which is between said shoe mechanism and each of said swash plate and said piston,  
       wherein said supply means comprises a gas passage which is formed in said piston and opens between said piston and said shoe mechanism and introduces said blowby gas together with said lubricating oil into said sliding portion. 
     
     
       2. A swash plate type compressor as claimed in claim  1 , wherein said piston has an outer peripheral surface with a particular portion which is always fitted in said cylinder bore even when said piston is reciprocated, said gas passage having an inlet formed at said particular portion. 
     
     
       3. A swash plate type compressor as claimed in claim  2 , wherein said piston has: 
       a hollow portion therein;  
       a ring-like groove circularly extending at said particular portion;  
       a radial through hole extending from said ring-like groove to said hollow portion; and  
       an axial through hole extending from said hollow portion to said sliding portion, a combination of said hollow portion, said ring-like groove, and said radial and said axial through holes serving as said gas passage.  
     
     
       4. A swash plate compressor as claimed in claim  1 , wherein said gas passage opens towards said shoe mechanism.